The dense and extensive reefs of the Surin Islands have the greatest hard coral diversity in Thailand. Though the soft corals and fish diversity are not as good as some of the other Andaman Sea destinations, you will find lots of turtles here and fish species that you won't see in the Similans, such as Napoleon wrasse, bumphead parrotfish, barramundi cod, yellow-mask angelfish and tomato anemonefish.
Not many liveaboard dive cruises visit these islands, not because the scuba diving in Surin is inferior to other Thai destinations, but rather due to the greater geographic remoteness and the short 4 day schedules of popular scuba safaris - not enough time to take in both the Similan and the Surin Islands. This means that when you do visit here, you'll find there's still a beautiful corner of Thailand that you can enjoy without sharing it with hordes of other tourists.
Located 7 km south of the Burmese border and 68 km north of the Similans, this island group was designated a national marine park in 1981 and is made up of 2 main islands - named Koh Surin Nua (North) and Koh Surin Tai (South) - plus 3 smaller islets and 2 rocky outcrops. The islands are uninhabited except for the national park camp and a traditional Mokken sea gypsy village (the same group that roam the Burma Mergui Archipelago). The world famous dive site of Richelieu Rock lies 15 km further to the east.
Along the east coast of Koh Torinla a hard coral plateau breaks the water's surface at low tide. Large fields of staghorn corals and massive porites corals dominate the shallows. Cardinalfish, humpnose bigeye bream, twin-spot and 5-lined snappers profilate. Just off the island's coast lies a 120 metre long rocky ridge that acts as a magnet for fish life. Pinnate batfish, barramundi, schools of bumphead parrotfish, blue-lined and pickhandle barracuda are common on the deeper east side that drops to 31 metres, and Spanish mackerel and grey reef sharks often pay fleeting visits to this island. White tip reef sharks frequently rest on the surrounding sands or can be spotted cruising the ridge top at 7 to 25 metres.
To get back to the reef slope you'll need to pass over an expanse of sand, where eagle rays and shovelnose rays occasionally travel. This area hosts mantis shrimps and the endemic Andaman, or blue-spotted, jawfish. You may be lucky to sight this most colourful family member hovering above its rubble burrow. Else you may be even luckier to see it peering out of its burrow, replete with a full brood of eggs delicately balanced in its protective mouth.
At the South East Point of Koh Surin Tai, 2 parallel jumbles of boulders run out perpendicular from the shallow reef flat into deeper water, where strong currents can whip up and attract reef sharks. Shelter in the refuges provided by these rocks and spend some time examining the soft corals and fans for harlequin ghostpipefish and robust ghost pipefish. Black and blue ribbon eels and cowrie shells also inhabit the rubble floor and crevices here.
Back on the reef slope you can capture your breath whilst ticking off Andaman rabbitfish, Indian sailfin tang and Andaman sweetlips (wite body with black dalmatain-like spots and yellow tail). The Surin Islands have some particularly attentive titan triggerfish, acting like over-protective parents guarding their unborn young - don't you just love 'em?
One of the major attractions of the Surin area is snorkelling. This is because in many places the reefs have grown right up to just a metre or so below the water's surface, bringing the marine life that much closer to the snorkeller. This is particularly so at Koh Torinla in the south and Koh Chi in the north. Here the reefs are very healthy and black tip reef sharks, conspicuous only by their absence from the Similan Islands, are regular visitors. This means Phuket liveaboard charters to the Surin Islands are ideal for non-divers and avid divers alike.
Many of Thailand's islands boast fantastic scenery and many visitors claim that the topside beauty of Surin's verdant evergreen forests, laced with small beaches and mangroves, surpasses even that of the Similans.
If you get the opportunity to take a walk through the forests then watch out for crab-eating macaques, flying lemurs and flying foxes, as well as deer and squirrels. Bird watchers can enjoy sightings of hornbills, Nicobar pigeons, collared kingfishers, drongos and babblers, as well as birds of prey such as sea-eagles and kites. Turtles still follow an age-old ritual to come ashore here and lay their eggs. The hatchlings enter the Andaman Sea and swim as far as the Nicobar Islands and the east coast of the Malay Peninsula.
Mid October to early May is the Surin liveaboard season. It can be too wet and windy outside of these months for dive boats to venture there. December to April is the best time for a visit.
The Surin area has a reputation for being a good place to spot large creatures like manta rays, eagle rays and even whale sharks. This is particularly the case for the period of February to April. Currents can kick up in this region during the November to January period which can mean great schooling action for fish such as trevallies, barracuda and fusiliers.
Warmer water temperatures are present during the dry season of November to April, peaking at 31°C. In the rainy season months from May to October, the water temperature dips but seldom if ever goes below 27°C. The best visibility also occurs in dry season, reaching up to 30m.
Great for: Reef life and health, snorkelling, small animals and beginner divers
Not so Great for: Wrecks
Depth: 5 - >30m
Visibility: 5 - 20m
Currents: Can be strong
Surface Conditions: Calm
Water Temperature: 26 - 29°C
Experience Level: Beginner - advanced
Number of dive sites: >10
Distance: ~205 km north northwest of Phuket (10 hours)
Access: Similan liveaboards from Phuket
Recommended length of stay: 5 - 6 days as part of a Thailand liveaboard cruise
Dive The World Thailand Recommendations: Koh Torinla and South East Point.